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An Identity Crisis?

There is a group of carnivores i often refer to as the “Big 4” of the Ice age, mainly for their prominence in discussions of the Pleistocene: Smilodon, dire wolf, Arctodus, and the American lion. That last one, it seems, is in the midst of having it’s identity changed.

The American lion was discovered in 1853. Joseph Leidy, one of the leading paleontologists of the time, named the animal from a jawbone brought to him from Mississippi. Since then many more fossils of the big cat have been found from Alaska to Mexico and from coast to coast.

American lion skull found in Alaska, displayed at the Smithsonian Museum of Natural History

The best remains come from the famous La Brea Tar Pits in California. So far over 80 individuals have been pulled from the black ooze, allowing a more complete picture of this animal. But it’s remains don’t extend to just bones. Enormous footprints from a cave in Missouri have been attributed to the American lion. What is more, a mummified bison carcass from Alaska was found with deep scratches on its back, bite marks across its muzzle, and a fragment of tooth in its hide, all testifying to this cat’s killing power.

But while it is often hailed as the biggest cat ever (some estimates exceed 700 pounds) it’s identity has always been a bit of a puzzle. It was long thought to be it’s own species, Panthera atrox; Panthera is the same genus in which lions, tigers, leopards, and jaguars belong. In recent times it was placed within the modern lion species as Panthera leo atrox. This made it the American subspecies of lion with the African lion as it’s closest relative. There have even been some suggestions that it wasn’t a lion but an American tiger! However a recent study has cast doubt on this classification.

Danish zoologist Per Christiansen and American paleontologist John Harris have done a study comparing the American lion to other big cats. They compared 23 skull dimensions of the American lion with other big cats and found something unusual. While it shared many features with lions it also had many features not seen in lions. Further more, it had features not shared with any big cats. But many features, like the lower jaw, linked it with the jaguar. So instead of being an American lion, it appears the Pleistocene of North America was home to a giant form of jaguar. The authors of the study suggest that the American “lion” may have descended from a group of pantherines that came to the New World in the mid Pleistocene (this group may also have spawned jaguars).

So what does this mean for the American “lion”? It is interesting that it is like a giant jaguar, since jaguars were known to have roamed Pleistocene North America. It may be that jaguars stuck to more forested areas while their larger cousins preferred open habitat. I feel though that the name lion will remain. It’s been in use for a very long time and has a sense of power and strength to it. It may be that as with many other prehistoric animals, the name of the beast will have to be explained to future generations as a slight misnomer.

Till next time!

Life-size model of the American "lion" at the San Diego Natural History Museum